There was 51 episodes for the 1st season and another 51 episodes for the 2nd season, that counts Shugo Chara's anime have been animated for at least 102 episodes ... and still continuing.

So yeah, Shugo Chara doesn't seem to be ending soon especially after the appearance of season 3 (which will probably add up to hundreds or even more episodes)

ps: don't click the spoiler below if you haven't been watching the seasons and don't want to be spoiled.
Here are some rough summary of the seasons:

Spoiler Alert! Click to show or hide

In Season 1:... The story is still centered on finding the Embryo and battling Easter.

In Season 2: ... New character named Nagihiko who is actually Nadeshiko from the previous season.... New character named Lulu came and it was also the first appearance for the Nazo (?) Eggs.... The story proceed until Amu and the Guardians found out the true form of Gozen and the true form of Embryo.... Ikuto went missing to search for his father's whereabouts.
In Season 3:...The season is divided to 2 sections: SC! Pucchi Pucchi *or however you spell it* and SC! Doki Doki and some random mini sections where the people from Shugo Egg 'entertain' the viewer with Fortune-Telling, etc....A new character named Rikka made her appearance and apparently she can talk to Batsu (X) Eggs...Dia is fully awaken from her (Egg)slumber...No sign of Ikuto for now

So I was just wondering, out of these 3 seasons (and currently 104 episodes) which season do you think is the best in its plot, music, etc. etc.?

- All of them were my favorite guardians. (Amu, Tadase, Nadeshiko, Kukai, Yaya)
- I really did Not want Rima to to come in!! I hate her so much! >3<
- My favorite character is NADESHIKO. I love her so much! She's so cute! >3<
- I liked Black Diamond and Meikyuu Butterfly.
- I LOVED X Dia.

1 - Because it still had the quality of story. Even the filler was of consequence. If it's filler, you shouldn't know it's filler. That is what I say and that is how the filler in Season 1 was. Actually Series 1 if you want to get technical.